1. Field of the Invention
The present invention relates to flexible foam slabstocks and methods of preparing the same. More specifically, the present invention relates to a process for reducing or preventing scorching of flexible foam slabstocks by using certain polyether polyols.
2. A Brief Description of the Prior Art
The use of polyether polyols as reactants with polyisocyanates in the preparation of flexible foam slabstocks is generally known in the art. It has been found that scorching is caused, at least in part, by the use of certain polyether polyols, e.g. acidified polyether polyols. The kind of scorching which is of concern here is the discoloration of foams due to high temperatures caused by the associated exothermic reactions.
Polyether polyols can be prepared by the polyaddition reaction of alkylene oxides and starter compounds having active hydrogen atoms, in the presence of basic catalysts. As is generally known, the resultant alkaline polyether polyols are purified by removing or deactivating the residual basic materials such as alkali metal hydroxides or metal salts which are employed in or result from the preparation of the polyether polyols. Known purification processes involve the use of various mineral or organic acids. It is believed that the manner in which the polyether polyol is treated during the purification process can, at least in part, cause the problem of scorching.
Attempts at solving the scorching problem with polyols neutralized by acidification have been unsuccessful. Varying the levels and types of antioxidants, for example, has been unsuccessful in reducing or preventing scorching of foam slabstock made with these polyols. By the present invention there is provided a process for reducing or preventing the problem of scorching.